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1

The progress of science from a computational point of view: the drive towards ever higher solvability

Marciszewski Witold

Foundations of Computing and Decision Sciences

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2019

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Vol. 44, No. 1

11--26

EN

This essay's content is rendered by the titles of the successive sections. 1. Effective solvability versus intuitive solvability. — 2. Decidability, i.e. effective solvability, in predicate logic. The speedup phenomenon — 3. Contributions of the second-order logic to the problems of solvability — 4. The infinite progress of science in the light of Turing's idea of the oracle. The term "oracle" is a technical counterpart of the notion of mathematical intuition. A more detailed summary can be obtained through juxtaposing the textboxes labelled with letters A...F. Conclusion: in the progress of science an essential role is played by the feedback between intellectual intuitions (intuitive solvability) and algorithmic procedures (effective solvability).

2

Parallel FDTD simulation using Task Parallel Library (TPL)

Bolesta I., Demchuk A.

Journal of Applied Computer Science

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2016

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Vol. 24, nr 2

7--16

EN

The finite-difference time-domain (FDTD) is a numerical analysis technique used for solving computational electrodynamic problems. The nature of the FDTD method is that simulation of big and complicated electromagnetic field problems requires a vast amount of computer operational memory and runtime. Parallel-processing techniques have been broadly applied to FDTD to accelerate the simulations. The parallelism of the FDTD algorithm is based on a fact that the computational domain can be divided into parts (sub-domains), and each processor in a parallel system deals with one or several sub-domains. The FDTD algorithm belongs to data parallelism model and can be effectively implemented on shared memory system architecture. The parallel FDTD method was implemented using TPL library. The Task Parallel Library (TPL) is a library for .NET that makes easy to parallelize the program using the advantages of .NET Framework. The speedup metrics of parallel FDTD algorithm were calculated and compared with Amdahl’s estimated speedup.

3

The Influence of Dynamic Characteristics of Vehicles on the Passenger Car Equivalent and Traffic Delay

Fornalchyk Ye., Mohyla I., Hilevych V.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2015

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Vol. 4, No 2

45--50

EN

The analysis of transportation flow andtechnical condition of cargo-carrying vehicles and buses has showed the need in the research of its influence on the passing density on signalized intersections. The indicator which reflects this influence is represented by light motor vehicle passenger car equivalent (PCE). The need in determining a passenger car equivalent for differently structured transportation flows is demonstrated not according to the recognized methodology, but according to the one developed by the authors which takes into account both diverse structure and the level of technical condition of road users. The latter one decreases launching dynamics of vehicles which depart from the stop line. The respective passenger car equivalents are determined for such a structure of traffic flow. These calculations differ from already known and normative ones. Due to the simulation (the VISSIM program) of passing at an intersection with the use of calculated passenger car equivalents which take into account the technical condition of vehicles, traffic delays on the main direction were defined as decreased by 7.6% for respective duration of permissive signal on a traffic light.

4

Transforming Source Code to Mathematical Relations for Performance Evaluation

Izadkhah H.

Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica

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2015

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Vol. 15, no. 2

7--13

EN

Assessing software quality attributes (such as performance, reliability, and security) from source code is of the utmost importance. The performance of a software system can be improved by its parallel and distributed execution. The aim of the parallel and distributed execution is to speed up by providing the maximum possible concurrency in executing the distributed segments. It is a well known fact that distributing a program cannot be always caused speeding up the execution of it; in some cases, this distribution can have negative effects on the running time of the program. Therefore, before distributing a source code, it should be specified whether its distribution could cause maximum possible concurrency or not. The existing methods and tools cannot achieve this aim from the source code. In this paper, we propose a mathematical relationship for object oriented programs that statically analyze the program by verifying the type of synchronous and asynchronous calls inside the source code. Then, we model the invocations of the software methods by Discrete Time Markov Chains (DTMC). Using the properties of DTMC and the proposed mathematical relationship, we will determine whether or not the source code can be distributed on homogeneous processors. The experimental results showed that we can specify whether the program is distributable or not, before deploying it on the distributed systems.

5

From quantity to quality: massive molecular dynamics simulation of nanostructures under plastic deformation in desktop and service grid distributed computing infrastructure

Gatsenko O., Bekenev L., Pavlov E., Gordienko Y. G.

Computer Science

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2013

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Vol. 14 (1)

27--44

EN

The distributed computing infrastructure (DCI) on the basis of BOINC and EDGeS-bridge technologies for high-performance distributed computing is used for porting the sequential molecular dynamics (MD) application to its parallel version for DCIwith Desktop Grids (DGs) and Service Grids (SGs). The actual metrics of the working DG-SG DCI were measured, and the normal distribution of host performances, and signs of log-normal distributions of Rother characteristics (CPUs, RAM, and HDD per host) were found. The practical feasibility and high efficiency of the MD simulations on the basis of DG-SG DCI were demonstrated during the experiment with the massive MD simulations for the large quantity of aluminum nanocrystals (Statistical analysis (Kolmogorov-Smirnov test, moment analysis, and bootstrapping analysis) of the defect density distribution over the ensemble of nanocrystals had show that change of plastic deformation mode is followed by the qualitative change of defect density distribution type over ensemble of nanocrystals. Some limitations (fluctuating performance, unpredictable availability of resources, etc.) of the typical DG-SG DCI were outlined, and some advantages (high efficiency, high speedup, and low cost) were demonstrated. Deploying on DG DCI allows to get new scientific quality from the simulated quantity of numerous configurations by harnessing sufficient computational power to undertake MD simulations in a wider range of physical parameters (configurations) in a much shorter timeframe.

6

Nośniki ceramiczne przyspieszające procesy fermentacji w bioreaktorach.

Zboromirska-Wnukiewicz B., Cybis E., Zubiński J.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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1998

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Vol. 34, nr 10

101-103

PL

Publikacje japońskie wskazują, że bioreaktory wyposażone w nośniki ceramiczne wpływają korzystnie na prowadzony w nich proces fermentacji i mogą powodować nawet dziesięciokrotne jego przyspieszenie bez pogarszania jakości produktu. Dla uzyskania wymienionych efektów, konieczne jest opanowanie szeregu elementów procesów fermentacji immobilizacyjnej i określenia własności nośników ceramicznych.

EN

It is stated in this work that at the fermentation process the ceramic immobile carriers play important role. The dependence between extinction coefficient and shape of ceramic carriers was investigated.